Decorate AuRaTxFilters in order to disable them post merge (#4182)

* Decorate AuRaTxFilters in order to disable them post merge

* Fix decorator for MinGasPriceContractTxFilter

* Redesign & Refactor

* Remove unused usings

Co-authored-by: lukasz.rozmej <lukasz.rozmej@gmail.com>

src/Nethermind/Nethermind.Consensus.AuRa/InitializationSteps/TxAuRaFilterBuilders.cs

@@ -29,6 +29,22 @@ namespace Nethermind.Consensus.AuRa.InitializationSteps
 {
     public static class TxAuRaFilterBuilders
     {
+        /// <summary>
+        /// Filter decorator.
+        /// <remarks>
+        /// Allow to create new filter based on original filter and a potential fallbackFilter if original filter was not used.
+        /// </remarks>
+        /// </summary>
+        public delegate ITxFilter FilterDecorator(ITxFilter originalFilter, ITxFilter? fallbackFilter = null);
+
+        /// <summary>
+        /// Delegate factory method to create final filter for AuRa.
+        /// </summary>
+        /// <remarks>
+        /// This is used to decorate original filter with <see cref="AuRaMergeTxFilter"/> in order to disable it post-merge.
+        /// </remarks>
+        public static FilterDecorator CreateFilter { get; set; } = (x, _) => x;
+
         private static ITxFilter CreateBaseAuRaTxFilter(
             IMiningConfig miningConfig,
             AuRaNethermindApi api,
@@ -40,15 +56,15 @@ private static ITxFilter CreateBaseAuRaTxFilter(
             ITxFilter gasPriceTxFilter = minGasPriceTxFilter;
             if (minGasPricesContractDataStore != null)
             {
-                gasPriceTxFilter = new MinGasPriceContractTxFilter(minGasPriceTxFilter, minGasPricesContractDataStore);
+                gasPriceTxFilter = CreateFilter(new MinGasPriceContractTxFilter(minGasPriceTxFilter, minGasPricesContractDataStore), minGasPriceTxFilter);
             }
 
             Address? registrar = api.ChainSpec?.Parameters.Registrar;
             if (registrar != null)
             {
                 RegisterContract registerContract = new(api.AbiEncoder, registrar, readOnlyTxProcessorSource);
                 CertifierContract certifierContract = new(api.AbiEncoder, registerContract, readOnlyTxProcessorSource);
-                return new TxCertifierFilter(certifierContract, gasPriceTxFilter, specProvider, api.LogManager);
+                return CreateFilter(new TxCertifierFilter(certifierContract, gasPriceTxFilter, specProvider, api.LogManager));
             }
 
             return gasPriceTxFilter;
@@ -65,7 +81,7 @@ private static ITxFilter CreateBaseAuRaTxFilter(
             {
                 RegisterContract registerContract = new(api.AbiEncoder, registrar, readOnlyTxProcessorSource);
                 CertifierContract certifierContract = new(api.AbiEncoder, registerContract, readOnlyTxProcessorSource);
-                return new TxCertifierFilter(certifierContract, baseTxFilter, specProvider, api.LogManager);
+                return CreateFilter(new TxCertifierFilter(certifierContract, baseTxFilter, specProvider, api.LogManager));
             }
 
             return baseTxFilter;
@@ -81,7 +97,7 @@ private static ITxFilter CreateBaseAuRaTxFilter(
             {
                 api.TxFilterCache ??= new PermissionBasedTxFilter.Cache();
 
-                var txPermissionFilter = new PermissionBasedTxFilter(
+                var txPermissionFilter = CreateFilter(new PermissionBasedTxFilter(
                     new VersionedTransactionPermissionContract(api.AbiEncoder,
                         api.ChainSpec.Parameters.TransactionPermissionContract,
                         api.ChainSpec.Parameters.TransactionPermissionContractTransition ?? 0, 
@@ -90,7 +106,7 @@ private static ITxFilter CreateBaseAuRaTxFilter(
                         api.LogManager,
                         api.SpecProvider),
                     api.TxFilterCache,
-                    api.LogManager);
+                    api.LogManager));
 
                 return txPermissionFilter;
             }

src/Nethermind/Nethermind.Merge.AuRa/AuRaMergePlugin.cs

@@ -1,22 +1,10 @@
 using Nethermind.Merge.Plugin;
 using Nethermind.Consensus.Transactions;
-using Nethermind.Consensus.AuRa.Transactions;
-using Nethermind.Consensus.Producers;
 using Nethermind.Consensus.Processing;
-using Nethermind.Evm.TransactionProcessing;
-using Nethermind.Consensus.AuRa.Contracts;
 using Nethermind.Consensus.AuRa.InitializationSteps;
-using Nethermind.Consensus.AuRa.Contracts.DataStore;
-using Nethermind.Core;
 using Nethermind.Db;
 using Nethermind.Blockchain;
-using Nethermind.Blockchain.Data;
-using System.Collections.Generic;
-using System.Runtime.CompilerServices;
-using Nethermind.Consensus;
-using Nethermind.Consensus.AuRa.Config;
 using Nethermind.State;
-using Nethermind.Specs.ChainSpecStyle;
 using System.Threading.Tasks;
 using Nethermind.Api;
 using Nethermind.Api.Extensions;
@@ -43,6 +31,10 @@ public override async Task Init(INethermindApi nethermindApi)
                 _auraApi = (AuRaNethermindApi)nethermindApi;
                 _auraApi.PoSSwitcher = _poSSwitcher;
                 _mergeConfig.Enabled = false; // set MergePlugin as disabled
+
+                // this runs before all init steps that use tx filters
+                TxAuRaFilterBuilders.CreateFilter = (originalFilter, fallbackFilter) =>
+                    new AuRaMergeTxFilter(_poSSwitcher, originalFilter, fallbackFilter);
             }
         }
 

src/Nethermind/Nethermind.Merge.AuRa/AuRaMergeTxFilter.cs

@@ -0,0 +1,26 @@
+using Nethermind.Core;
+using Nethermind.TxPool;
+using Nethermind.Consensus.Transactions;
+using Nethermind.Consensus;
+
+namespace Nethermind.Merge.AuRa
+{
+    public class AuRaMergeTxFilter : ITxFilter
+    {
+        private readonly IPoSSwitcher _poSSwitcher;
+        private readonly ITxFilter _preMergeTxFilter;
+        private readonly ITxFilter _postMergeTxFilter;
+
+        public AuRaMergeTxFilter(IPoSSwitcher poSSwitcher, ITxFilter preMergeTxFilter, ITxFilter? postMergeTxFilter = null)
+        {
+            _poSSwitcher = poSSwitcher;
+            _preMergeTxFilter = preMergeTxFilter;
+            _postMergeTxFilter = postMergeTxFilter ?? NullTxFilter.Instance;
+        }
+
+        public AcceptTxResult IsAllowed(Transaction tx, BlockHeader parentHeader) =>
+            _poSSwitcher.IsPostMerge(parentHeader)
+                ? _postMergeTxFilter.IsAllowed(tx, parentHeader)
+                : _preMergeTxFilter.IsAllowed(tx, parentHeader);
+    }
+}

src/Nethermind/Nethermind.Merge.Plugin/MergePlugin.cs

@@ -58,9 +58,9 @@ public partial class MergePlugin : IConsensusWrapperPlugin, ISynchronizationPlug
         protected IPoSSwitcher _poSSwitcher = NoPoS.Instance;
         private IBeaconPivot? _beaconPivot;
         private BeaconSync? _beaconSync;
-        private IBlockCacheService _blockCacheService;
+        private IBlockCacheService _blockCacheService = null!;
         private InvalidChainTracker.InvalidChainTracker? _invalidChainTracker;
-        private IPeerRefresher _peerRefresher;
+        private IPeerRefresher _peerRefresher = null!;
 
         private ManualBlockFinalizationManager _blockFinalizationManager = null!;
         private IMergeBlockProductionPolicy? _mergeBlockProductionPolicy;
@@ -246,11 +246,11 @@ public Task InitRpcModules()
                 }
 
                 PayloadPreparationService payloadPreparationService = new(
-                    _postMergeBlockProducer, 
-                    improvementContextFactory, 
-                    _api.Sealer, 
+                    _postMergeBlockProducer,
+                    improvementContextFactory,
+                    _api.Sealer,
                     _api.TimerFactory,
-                    _api.LogManager, 
+                    _api.LogManager,
                     TimeSpan.FromSeconds(_mergeConfig.SecondsPerSlot));
 
                 IEngineRpcModule engineRpcModule = new EngineRpcModule(